The general aim is to establish the number and arrangement of the 5 collagen genes in the chicken and human genome and to learn as much as possible about the way they are selectively expressed and totally repressed. The starting point is the isolation of the corresponding procollagen mRNAs and their cDNAs and using these to titrate the genes, examine their mutual arrangement, locate the genes on the chromosomes and to undertake an extensive plasmid amplification program. The result of this program will be the production of sets of sequences in and adjacent to some of the collagen genes. With these the role of Hn RNA, specific regulatory sequences and regulatory proteins can hopefully be identified. The ultimate goal would be to isolate a complete collagen gene with its regulatory sequences and appropriate proteins. This approach would be complemented by using assays based on partially reconstituted chromatin to search for regulatory proteins contained in the nucleus of collagen producing and non-producing cells.